1. Field of the Invention
The present invention relates to a crystalline α-D-glucosyl α-D-galactoside which has a melting point of 119–123° C., a saccharide composition comprising the same, a process for producing the same, uses thereof, and a method to convert an amorphous α-D-glucosyl α-D-galactoside to a crystalline α-D-glucosyl α-D-galactoside.
2. Description of the Prior Art
Patent document No. 1: A Patent Kokai No. 304,881/98.
Non-patent document No. 1: “Carbohydrate Research”, Vol. 50, pp. 152–157, 1976, by C. K. Lee et al.
Non-patent document No. 2: “Carbohydrate Research”, Vol. 239, pp. 197–207, 1993, by R. W. Bassily et al.
An α-D-glucosyl α-D-galactoside is a non-reducing disaccharide, which glucose and galactose are linked each other via the α,α-1,1 linkage, and is an isomer of α,α-trehalose (hereinafter abbreviated as “trehalose”). Non-patent document Nos. 1 and 2 disclose an α-D-glucosyl α-D-galactoside which is organically synthesized, and the document No. 2 discloses its crystalline monohydrate with a melting point of 165–170° C. However, the above processes are complicated organic syntheses, their yields are relatively-low, it is difficult to produce them with a large quantity, and not only uses thereof but also an industrial production have not been developed at all. Thereafter, the same applicant as the present invention disclosed the synthesis of α-D-glucosyl α-D-galactoside by an enzymatic method using trehalose phosphorylase in the patent document No. 1 to enable to produce it with a large quantity.
α-D-Glucosyl α-D-galactoside has a fine sweetness; properties such as regulation of osmotic pressure, moisture absorption, gloss imparting ability, ability of preventing crystallization of other saccharides, and ability of preventing deterioration of starch; and functions such as cariostatic ability, ability of promoting growth of bifidobacterium, and ability of promoting absorption of minerals. Therefore, α-D-glucosyl α-D-galactoside has uses for many compositions such as food products, favorite foods, feed, baits, cosmetics, medicated cosmetics, pharmaceuticals, goods for life, products for agriculture, forestry and fisheries, reagents, and products for chemical industries. However, amorphous α-D-glucosyl α-D-galactoside had a problem of unstability, for example, the saccharide alone or a composition of other saccharide had a relatively-high moisture absorption and easily solidified, deliquesced, or lost fluidity. Therefore, it has not been easily applied in many fields in spite of its various usefulness.